Though H2O Audio's Interval ($80) is a little bit late out of the starting gate given the discontinuation of the second-generation iPod shuffle it depends upon, this new swimmers' accessory might be reason enough to maintain demand for Apple's prior-generation screenless audio player. Based upon the earlier iSH2, which combined a waterproof iPod shuffle case with a pair of H2O Audio's headband-styled waterproof headphones, Interval preserves the case but replaces the headphones with the company's superior Surge model. The result is a best-of-class underwater listening option for the shuffle, with only one caveat that will impact certain users.

The core of Interval is a black hard plastic and gray rubber box that holds the second-generation iPod shuffle snugly inside, using a pressure clasp to seal the enclosure tight against water intrusion. Once again, it promises to keep your shuffle safe when submerged in water at up to 12-foot depths, and permits access to the device’s front-mounted play/pause, volume, and track controls; you need to flip the power and/or shuffle mode switches yourself before closing the case. As H2O Audio has been making these cases for years, and is now on its third iPod shuffle 2G product, there wasn’t any surprise in Interval’s performance: it kept our shuffle completely dry in extended submersion tests, provided easy front control access, and added what might be called “minimal” weight given what it’s attempting to do; surely, future versions for smaller iPods will be even lighter.

Interval also comes packaged with a number of other items. Five total sets of rubber tips ranging from extra small to extra large are included in the box, as is a Surge-alike rubberized, zippered carrying case for all of the parts. The integrated earbuds are just like Surge’s, save for the dramatically diminished cabling: roughly 8 inches of black, rubberized wire separate each earbud from the housing, which is plenty of length to let the buds sit in your ears with Interval sitting behind the back of your head. All you need to do is remember the button configuration—up for volume up, down for volume down, left for track back, and right for track forward—and using the shuffle is easy.

To make a point previously found in the Surge review, these earbuds are excellent by waterproof earphone standards: as we said last year, “the sonic difference [between Surge and prior models] is considerable: what you hear is legitimately balanced, clear sound, complete with ample bass and none of the tinny, shrill emptiness that typically characterizes waterproof headphones.” Their tips seal well, and avoid all of the discomfort and other oddities that went along with the headband-mounted H2O designs. In short, getting these earphones rather than the old ones for the same price as iSH2 makes this a hugely superior offering.

There is one catch. Whereas iSH2 was capable of serving either as a standalone listening system—self-mounted thanks to an integrated headband—or as a case that mounted itself on swimmers’ goggles, Interval is designed solely to be used with goggles. Two goggle-ready clips are found on its back, and attach to the bands that pro swimmers rely upon underwater. If you’re not wearing goggles, Interval can still be worn behind your head, and the earbuds may still stick in your ear canals, but you’ll be lucky to maintain a great seal if you’re doing any type of real movement underwater. Between the shuffle’s and the case’s weight, there’s just enough drag on the earbuds to make them less than perfectly stable when used improperly.

Our high recommendation of Interval is, of course, based on proper usage rather than the way some people would love to use it—in its current form, this is a fantastic swimmers’ accessory that users without goggles will envy. Thankfully, there’s still the option of iSH2, albeit with a headband and diminished audio quality. We’d imagine that H2O will be bitten by the temptation to evolve this design into a smaller and even lighter third-generation iPod shuffle version with integrated controls; it will be interesting to see at that point whether goggles are even necessary for the shuffle’s stability.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.